s = pool_elt_at_index (tsm->sessions, oldest_elt->value);
sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);
s = pool_elt_at_index (tsm->sessions, oldest_elt->value);
sess_timeout_time = s->last_heard + (f64) nat44_session_get_timeout (sm, s);